Hydrogen Storage Capacity of Pd Particles Dispersed in Mesoporous Silicas
Hydrogen Storage Capacity of Pd Particles Dispersed in Mesoporous Silicas
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介孔二氧化硅中分散的钯颗粒的储氢能力
DOI：
10.1166/jnn.2016.13660
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发表时间：
2016
影响因子：
--
通讯作者：
Tomoyoshi Motohiro
中科院分区：
文献类型：
--
作者：
Yoshiki Ichikawa;Tatsumi Hioki;Noriaki Sugimoto;Akihisa Ichki;Tomoyoshi Motohiro
以介孔氧化硅TMPS为载体，研究了Pd纳米粒子的尺寸效应对吸氢性能的影响。由于吸氢热的作用，Pd纳米颗粒在氢气中容易长大。这种效应使得难以评估纳米尺寸的Pd颗粒的真正的吸氢性能。在本研究中，嵌入TMPS介孔中的钯纳米颗粒预计在暴露于氢气时难以生长，因此通过常规初湿浸渍，然后用正辛烷冲洗，合成了TMPS中高度分散的钯纳米颗粒，其中钯前体溶液粘附到TMPS的外壁可以被完全去除。X射线衍射（XRD）和透射电子显微镜（TEM）分析结果表明，Pd纳米粒子嵌入TMPS介孔中，在氢气气氛下具有较高的稳定性。它们的几个纳米的颗粒尺寸与暴露于氢气中没有变化，并且仅取决于主体材料的孔径。嵌埋在TMPS中的Pd纳米颗粒的吸氢容量小于Pd本体的吸氢容量。在0.01 MPa和室温下，尺寸为约2.5和4.0 nm的Pd纳米颗粒的H/Pd比分别为0.48和0.49。这些结果接近两个先前报道的值，在类似的压力和温度条件下，在不同的方法约束的类似大小的Pd纳米粒子。
Nano-size effects on hydrogen absorption properties were investigated with Pd nanoparticles loaded on the mesoporous silica named TMPS. The size of Pd nanoparticles is easy to increase when exposed to hydrogen owing to the heat of hydrogen absorption. This effect makes it difficult to evaluate the genuine hydrogen absorption properties of nano-sized Pd particles. In this study, Pd nanoparticles embedded into the mesopores of TMPS were expected hard to grow upon exposure to hydrogen, and thereby highly dispersed Pd nanoparticles in TMPS were synthesized via conventional incipient wetness impregnation followed by washing out with n-octane, where the Pd precursor solution adhered to the outer walls of TMPS could be removed completely. X-ray diffraction (XRD) patterns and transmission electron microscopic (TEM) images confirmed that Pd nanoparticles embedded into the mesopores of TMPS had a high stability under hydrogen atmosphere. Their particle size of a few nanometers was unchanged with exposure to hydrogen and only depended on the pore size of the host materials. Hydrogen absorption capacities of Pd nanoparticles embedded into TMPS were smaller than that of Pd bulk. The H/Pd ratios at 0.01 MPa and room temperature for Pd nanoparticles with a size of about 2.5 and 4.0 nm were 0.48 and 0.49, respectively. These results were close to the two previously reported values for a similar size of Pd nanoparticles constrained in different methods under similar pressure and temperature conditions.